352 Transactions. — Geolof/y. 



steam. Mr. E. Arthur, of Mount Eden, who had a distinct 

 view of the cloud iUumined by electric flashes on the morning of 

 the 10th, took notice of the height which it appeared as seen 

 behind One Tree Hill ; and the angle of elevation, as afterwards 

 measured by Mr. Vickerman, of the Survey Department, gives a 

 height, as computed by him, of 44,700 feet above Ruawahia, or 

 a little over 8 miles. Although this method of observation is 

 not a very accurate one, and may not be quite correct, it gives 

 some approximation to the height.* We know from actual 

 measurement that the column of steam arising from Rotoma- 

 hana several days after the eruption was 15,400 feet, and even 

 then the top of the column could not be seen, from its proximity 

 to the observer. The ashes and dust ejected fell on the coast 

 line at points 160 miles apart in a straight line — viz., at Tairua 

 and at An aura, a few miles north of Gisborne, and some of it 

 fell on the s.s. " Southern Cross " off the East Cape, and on 

 the s.s. " Wellington " near Mayor Island. It thus covered an 

 area of land equal to 5,700 square miles with more or less of the 

 deposit ; on the edges of which, of course, it is barely visible. 



In thus calling attention to the great height to which the 

 dust and ashes were projected by the explosive force of the 

 steam, a distinction must be drawn between this height and 

 that mentioned by Professor Verbeek. In the Tarawera case 

 this refers to the top of the cloud of ashes ; in that of Krakatoa 

 to the column of steam seen long after the eruption. Nor must 

 it be inferred that in the New Zealand eruption we shall neces- 

 sarily see the same extraordinary and beautiful atmospheric 

 effects which followed the Sunda eruption. 



The electric phenomena accompanying the outburst must 

 have been on the grandest scale. The vast cloud appears to 

 have been highly charged with lightning, which was Hashing 

 and darting across and through it : sometimes shooting upwards 

 in long curved streamers, at others following horizontal or 

 downward directions, the flashes frequently ending in balls of 

 fire, which as often burst into thousands of rocket-like stars. 

 Fire-balls fell at the Wairoa and other places, and doubtless the 

 fires which occurred at Mr. Hazards house and in the forest 

 near Lake Tarawera were due to these. 



Earthquakes. 



The earthquakes appear to have been almost continuous 

 from 1 a.m. to 3.30 a.m., with heavier shocks at about 4.30 

 and about 5.30, which were felt over a large district, extending 

 in an east and west direction from Te Aroha, where they were 

 slight, to Opotiki, where 71 separate shocks were felt ; and in a 

 north and south direction from the coast to Taupo. Although 



• Archdeacon Williams, of Gisborne, who saw the flashes of lightning on 

 the 10th, calculates that they were seen at an elevation of 6 miles. 



